On tax measures, Reform estimates that increasing the tax-free threshold by £2,430 would save most taxpayers £500 a year and 2.9 million people would stop paying income tax altogether.
It says the policy would cost £17.7bn in the first year, rising to £21bn by the fifth year and could be paid for through £80bn of public spending cuts the party plans to make.
Jenrick told BBC Breakfast Reform would pay for the policy by “cutting out the waste”.
Reform has said its spending cuts would include a £50bn reduction in welfare spending.
Half of the £353bn of welfare spending goes on the state pension, but Reform has said it will not cut this proportion.
The bulk of the funding would come from reducing the cost of welfare, Jenrick said, by not paying benefits to people who are not British citizens and helping people who are off work due to their mental health back into jobs.
Jenrick also said the UK would “stop paying foreign aid to rich countries”, adding that “we should be looking after British people first”.
“Yes, we’ll pay for disaster relief but the vast majority of that budget should be spent on the priorities of our own people,” he said.
Reform hopes to raise £10bn by scrapping net-zero programmes and Jenrick said, as the UK only amounted to 1% of the world’s emissions, it was not sensible to be trying to decarbonise faster than other countries as that was “just impoverishing our own people”.
The party hopes to raise £8bn by reducing the number of civil servants and £7.1bn by capping the foreign aid budget.
The policy is expected to be announced in Jenrick’s conference speech later.
“As chancellor, I will wake each morning with one purpose. To make Britain a better place to be a worker than it was the day before,” he is expected to say.
He is expected to add: “1.3 million were dragged into paying tax last year alone. Why? Because the tax-free allowance has been stuck at 12 and a half grand since 2021. And Labour has frozen it until 2031.
“That betrayal costs a full-time worker on the minimum wage more than £750 a year. And now for the first time, the freeze means they’re going to be taxing the state pension. What a disgrace.”
In its manifesto before the general election in 2024, Reform said it wanted to lift the threshold to £20,000. Jenrick will tell conference activists this remains his long-term aim.
The personal allowance threshold currently stands at £12,570. Anyone earning more than £100,000 starts to lose their personal allowance. For every £2 earned above the threshold the basic allowance decreases by £1.
Shortly after becoming prime minister, Andy Burnham told the Times that the “frustration” of people in his Makerfield constituency about the frozen allowance had “lodged in my mind”.
He later said that “all of this would be looked at” in the upcoming Budget but that any change would be “difficult given the financial circumstances”.
